A vegetarian is someone who does not eat meat, poultry, or fish but continues to eat plant-based foods and, depending on the type of vegetarianism they follow, may also include dairy products and eggs. It’s one of the most widely adopted dietary patterns in the world, driven by a mix of health, ethical, and environmental motivations.
Types of Vegetarian Diets
Not all vegetarians eat the same way. The differences come down to which animal-derived products, besides meat and fish, a person is willing to include.
- Lacto-ovo vegetarian: The most common type. Includes plant foods, dairy products, and eggs. No meat, poultry, or seafood.
- Lacto vegetarian: Includes plant foods and some or all dairy products, but no eggs, meat, poultry, or seafood.
- Ovo vegetarian: Includes plant foods and eggs, but no dairy, meat, poultry, or seafood.
- Vegan: Excludes all animal-derived products, including dairy, eggs, and often honey.
You’ll also hear the term “semi-vegetarian” or “flexitarian” for people who eat a mostly plant-based diet but occasionally include meat or fish. Pescatarians eat fish but skip other meats. These aren’t technically vegetarian, but they often get grouped into the same conversation.
Why People Become Vegetarian
Animal welfare is the single most common motivator for choosing a vegetarian diet, followed by concern over the environmental impact of animal agriculture. Health ranks as the third major driver, with general well-being and weight management cited most often. Many people are motivated by more than one of these reasons at the same time, and priorities can shift over the years. Someone who starts out for health reasons may stay for ethical ones, or vice versa.
Health Benefits
A well-planned vegetarian diet is linked to meaningfully lower rates of several chronic diseases. The cardiovascular benefits are particularly well documented: vegetarians show a 25% lower risk of developing or dying from ischemic heart disease compared to non-vegetarians. A large meta-analysis of 13 studies found a 15% reduction in overall cardiovascular disease risk among vegetarians, though stroke risk was not significantly different.
The benefits extend to blood sugar regulation. In a major study of more than 60,000 adults (the Adventist Health Study-2), lacto-ovo vegetarians had roughly 38% lower odds of developing type 2 diabetes compared to non-vegetarians, even after controlling for body weight, physical activity, and other lifestyle factors. Vegans showed an even larger reduction, with about 62% lower odds.
These outcomes likely reflect the overall dietary pattern rather than any single food. Vegetarian diets tend to be higher in fiber, potassium, and antioxidants, and lower in saturated fat. That combination helps with blood pressure, cholesterol, and insulin sensitivity over time.
Nutrients That Need Extra Attention
Cutting out meat removes the most concentrated source of a few key nutrients. With some awareness, all of them can be managed through food choices or supplements.
Vitamin B12
This is the nutrient vegetarians are most likely to fall short on, because it’s found almost exclusively in animal products. Adults need about 2.4 micrograms per day. Lacto-ovo vegetarians can get some B12 from eggs and dairy, but levels are often still below optimal. A daily supplement of 50 to 100 micrograms is a common preventive recommendation for vegetarians. Fortified foods like plant milks, nutritional yeast, and breakfast cereals can also contribute.
Iron
Plants contain a form of iron (non-heme iron) that your body absorbs less efficiently than the iron in meat. That doesn’t mean vegetarians are destined for deficiency, but it does mean you need to be strategic. Vitamin C dramatically improves absorption: eating citrus, bell peppers, or tomatoes alongside iron-rich foods like lentils, beans, or spinach makes a real difference. Fermented foods like sourdough bread also help by breaking down compounds that block iron uptake.
On the flip side, tea, coffee, and cocoa contain polyphenols that bind to iron and reduce absorption. Calcium does the same. If you’re concerned about iron, spacing your coffee or tea away from meals by an hour or two is a simple adjustment that helps.
Other Key Nutrients
Omega-3 fatty acids, calcium (especially for vegans and ovo vegetarians who skip dairy), iodine, and zinc all deserve attention. These become especially important during pregnancy and breastfeeding, when nutrient demands increase. Health organizations support vegetarian diets during pregnancy as long as they are well-planned and include appropriate supplementation of B12, iron, calcium, omega-3s, and iodine.
Getting Enough Protein
Protein is the nutrient vegetarians get asked about most, and it’s the one that’s actually easiest to manage. Plant-based protein sources are varied and widely available.
- Seitan: 25 grams of protein per 3.5 ounces (100 grams), making it the most protein-dense plant option
- Tempeh: About 30 grams per cup
- Tofu: 20 to 40 grams per cup, depending on firmness
- Lentils: About 18 grams per cup, cooked
- Chickpeas and most beans: About 15 grams per cup, cooked
Eating a variety of these foods throughout the day provides all the essential amino acids your body needs. The old advice about carefully “combining” proteins at every meal has been largely set aside. As long as your overall diet includes a range of legumes, grains, nuts, and seeds, your protein needs are covered.
Environmental Impact
The environmental case for vegetarianism is backed by increasingly detailed data. In a study comparing the daily carbon footprints of different dietary patterns, meat eaters generated an average of 3.62 kg of CO2 equivalent per day, while vegetarians produced 2.45 kg. That’s a roughly 32% reduction. Vegans came in lowest at 1.38 kg per day.
When adjusted for calorie intake, the gap widens further. Per 1,000 calories consumed, a meat-based diet generates about 58% more greenhouse gas emissions than a vegetarian diet. Animal agriculture also uses significantly more land and water than plant farming, which is a major reason environmental organizations frequently point to reduced meat consumption as one of the most impactful individual actions for lowering your carbon footprint.
Vegetarianism Across the Lifespan
A vegetarian diet can work at every stage of life, from childhood through older adulthood, with appropriate planning. The key nutrients to watch don’t change much, but the stakes are higher during periods of rapid growth or increased demand: pregnancy, breastfeeding, childhood, and adolescence. During these times, regular monitoring of B12, iron, and other critical nutrients through blood work helps catch any shortfalls early.
For older adults, the focus shifts slightly toward protein intake (muscle maintenance becomes a priority) and B12 absorption, which naturally declines with age regardless of diet. Vegetarians who already supplement B12 may actually be ahead of omnivores who assume they’re getting enough from food alone.